Multi-band resonant v antenna



June 4, 1963 J. M. JAYTANIE MULTI-BAND RESONANT v ANTENNA 3 Sheets-Sheet 1 Filed Oct. 4, 1960 @EMMNEQ -LULF INVENTOR fiszpH/Mfiynywa June 4, 1963 J. M. JAYTANIE MULTI-BAND RESONANT V ANTENNA Filed Oct. 4, 1960 s Sheets-Sheet 2 r- SNVENTOR I JESEPH M -77 YTq/v E /v ATTORNEY June 4, 1963 J. M. JAYTANIE MULTI-BAND RESONANT v ANTENNA 3 Sheets-Sheet 3 Filed Oct. 4, 1960 bobw omTL -ONFF United States 3,092,835 MULTI-BAND RESONANT V ANTENNA Joseph M. Jaytanie, Sherburne, N.Y., assignor to Technical Appliance Corporation, Sherburne, N.Y., a corporation of New York Filed Oct. 4, 1960, Ser. No. 60,505 9 Claims. (Cl. 343-802) This invention relates to an antenna that is especially designed for high gain over a wide radiation frequency band, and which is capable of retaining highly directional effects over such a band.

A principal object of the invention is to provide an improved directionalized antenna which is capable of highly eflicient operation over two widely spaced frequency bands, for example the presently assigned low frequency band of television channels 2 through 6 (54 to 88 megacycles), and in the higher frequency band of television channels 7 through 13 (174 to 216 megacycles).

Another object is to provide uniform coverage of low band frequencies of the low band channels 2-6, and high band frequencies of the television channels 7-13, with higher gain on the latter channels. This feature is advantageous in the reception of color television transmission, since a flat response curve is required to produce uniformity in color picture.

Another object is to provide an antenna that has a single forward lobe on all channels, which will maintain a high front-to-back ratio on all channels, and has radiation characteristics which are free of minor or side lobes on all the desired channels. As a result, there is a minimization of adjacent channel interference, co-channel interference, noise interference and disturbing reflections.

Another object is to provide a wide frequency band receiving antenna having a plurality of driven dipole units for connection to a single feed line. Two of the dipole units being of the folded dipole type, are especially designed to act as half-wave dipoles over the entire low frequency band while at the higher frequency band they act as three end-fed, half-wave elements whose signals add in phase by a series connection. The said dipoles are in the form of forward -Vs to give greater bandwidth at the lower frequency band while at the higher frequency band producing a large output voltage by virtue of the space relationship of the three half-wave sections. The operation on the high band can be further enhanced by the addition of impedance matching stubs which are attached to the dipoles to provide eificient impedance transfer at the dipole terminals. Two of the remaining dipole units are effective half-wave dipoles on the lower frequency bands having a wide terminal spacing, so that impedance matching can be accomplished by tapering feed lines. These latter dipoles are eifectively two endfed co-linear dipoles on the higher frequency band with current flowing in the same phase relationship.

A feature of the invention relates to the novel organization, arrangement and relative location and interconnection of parts which cooperate to produce an improved highly directionalized wide band antenna.

Other features and advantages will become apparent after considering the following detailed description and the appended claims. In the drawing,

FIG. 1 is a top plan view of an antenna system according to the invention;

FIG. 2 is a perspective view of the system of FIG. 1 showing more clearly the manner of mechanical support of the various elements of the system;

FIG. 3 is a view of one of the dipole elements of FIGS. 1 and 2, showing the current distribution at various sections of the unit;

FIG. 4 is a view of another one of the dipole elements senses Patented June 4, 1963 of FIGS. 1 and 2, showing the current distribution at various sections of the unit;

FIG. 3A is a relative voltage pattern on the lower end of the frequency band corresponding to the elements of FIG. 3;

FIG. 3B is a relative voltage pattern on the upper end of the frequency band corresponding to the element of FIG. 3;

FIG. 4A is a relative voltage pattern on the lower end of the frequency band corresponding to the element of FIG. 4;

FIG. 4B is a relative voltage pattern on the upper end of the frequency band corresponding to the element of FIG. 4;

FIG. A is a relative power pattern or directivity diagram of the system of FIGS. 1 and 2 on the lower end of the frequency band;

FIG. 5B is a relative power pattern or directivity diagram of the system of FIGS. 1 and 2 on the upper end of the frequency band.

*Referring to FIG. 1, the antenna therein shown comprises four dipole units 1, 2, 3, 4. Units 1 and 2 are preferably of the folded dipole construction, for example constructed of rigid wire rods 15 and whose physical lengths are chosen so that at the lower frequency band (54 to 88 rnegacycles) they operate as half-wave antennas. These dipoles may be straight rods or dipoles of the folded or stepped-up ratio type. Rods 15 and 20 are folded in accordance to the well known folded dipole theory so as to provide a pair of relatively closely spaced feed points 48, 49 and 50, 51 designed to impart the desired half-wave operation at the lower frequency. The units 1, 2 may, for example, have an overall dimension of 99 inches. Mounted in close parallel relationship to units 1, 2 are wire rods 17, 18 and 22, 23 which are conductively attached to the dipoles at points 52, 53 and 54, 55 respectively. These wire rods are supported at their free ends by dielectric spacers 16, 19 and 21, 24. On dipole unit #1 the said wire rods are located at points 52, 53 which are spaced about 22 inches from the open ends 48, 49, for example AM from the ends 48, 49. Located at points 54, 55 on dipole unit #2 the wire rods are spaced about 17 /2 inches from the open ends 50, 51. The overall length of each of said wire rods 17, 18, 22, 23 may be 10 inches per rod. I have found that these wire rods or stubs are substantially ineffective on low band operation, but shift the basic impedance of their respective folded dipoles to a more favorable value in a multi element system such as that shown in the drawing.

The dipole units 3, 4 are constructed of wire rods 25, 27 and 28, 30. The effective overall length of each unit 3 and 4 is a half wavelength dipole on television channels 4 and 5 respectively. Elements 25, 27 are for example eftective half-wave dipoles on the lower frequency television channels, while elements 28, 30 are efiectively half-wave dipoles on the higher frequency television channels. The dipole units 3, 4 are fed through tapered lines 38, 39 and 42, 43 in such a manner that in-phase currents anive at junction points 56, 57 and 58, 59. Thus, the spacing between the free ends a and 27a is large as compared with the spacing between the ends 48, 49 and 50, 51 of the folded units 1 and 2. The wire rods 25, 26, 27 of unit 3 are supported in rigid co-linear relationship by rigid insulator spacers 100, 102. Likewise, wire rods 28, 29, of unit 4 are supported in rigid colinear relationship by insulator spacers 103, 104. The spacing between the ends 25a and 27a and between the ends 28a and 30a may be as much as 23 inches. Thus, by widely spacing the said dipole arms 25 and 27, the intervening elements 26 and 29 can be used as parasitic directors.

angle which is equal to about 90 degrees.

The dipole unit #2 is spaced from dipole unit #1 a physical distance S plus 8., which may be 22 inches. Dipole unit 3 is spaced from unit 2 a distance which is equal to the sum of spacings S S and This dimension may for example be 36 inches. Dipole unit 4 is spaced from unit 3 a distance which is equal to spacing 8;, plus S This dimension may be 21 inches. Each of the conductors of the tapered feed lines 38, 39 and 42, 43 is a straight wire or rod element and may be approximately 17 /2 inches long. These feed lines join the main transmission line T leading to the radio receiver or transmitter (not shown), at junction points 56, 57 and 58, 59 respectively, which junction points are spaced from the dipole units 3, 4 a distance which is equal to S or S for example, they may be about 13 inches.

Mounted in spaced relation to and forwardly in front of units 1, 2 are parasitically driven directors 7, 8 consisting of metal rods which may be 22 inches long. The spacings S between units 1 and 7, and S between units 2 and 8 may be approximately 8 /2 inches. Mounted in spaced parallelism and co-linear with dipole units 3, 4

are parasitically driven directors 26, 29 consisting of metal rods which may be approximately 21 /2 inches long. Mounted in front of dipole unit 2 is a parasitically driven V-shaped director 9 consisting of a metal rod which is spaced a distance equal to S and S This spacing may be about 22 inches. The overall length of this director may be approximately 43 inches. This director is a forward V having an included or opening Mounted in spaced parallelism to and in front of unit 4 is a parasitically driven director unit 10 consisting of three colinear spaced metal rods 31, 32, 33. The wire rods 31, 32, 33 of the parasitic director unit 10 are supported in rigid co-linear relationship by insulator spacers 105, 106. Rods 31, 33 may be about 22 /2 inches long; rod 32 may be about 21% inches long. The spacing S between unit 10 and unit 4 may be about 5 /2 inches. Mounted in spaced parallelism to and in front of the director unit 10 is still another parasitically driven director unit 11 consisting of two co-linear half-wave metal rods 34, 35 each of which may be about 23 /2 inches and joined at their adjacent gapped ends by two one-quarter wave stub transmission lines 36, 37.

Mounted in spaced relation to and in the rear of dipole unit 1 is a parasitically driven reflector unit 6 consisting of three related reflector units 12, 13, 14. The unit 6 is a forward V having an included or opening angle which is equal to approximately 120 degrees. The elements 12, 14 of reflector 6 are metal rods whose physical length may be approximately 36 inches, while element 13 is a metal rod which may be approximately 34 inches. The wire rods 12, 13, 14 of the parasitic reflector unit 6 are supported in a rigid co-linear relationship by insulator spacers 197, 108. The spacing S between units 1, 6 may be approximately 17 inches. Mounted in spaced relationship to and in the rear of unit 6 is another parasitically driven reflector unit '5 consisting of a metal rod which may be approximately 110 inches long. The spacing S between units 5, 6 may be approximately 10 inches.

The various dipole units and parasitic units may then be mounted on a suitable boom as shown in FIG. 2. The mounting boom is shown a consisting of two parallel members 62, 63. Instead of a two-boom construction, all the antenna elements may be mounted on one boom. If the boom is of metal, elements 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 may be directly attached at points 66, 68, 71, 72, 64, 65, 67, 69, 7t), 73 respectively, since they need not be insulated. While the gapped adjacent ends of units 1, 2, 11 and tapered lines 38, 39 and 42, 43 may be supported by insulator spacers '74, 75, 78, respectively, as described in US. Patent 2,705,283. In order that the antenna be streamlined and sturdy with the capabilities of withstanding extreme Weather and icing conditions,

the unit elements are preferably mounted on two parallel support booms 62, 63, boom 62 has a length of approximately 126 inches while boom 63 has a length of approximately 69 inches. The two booms are then united by clamps (not shown). The booms are provided with the usual U-bolts (not shown) to facilitate mounting onto a vertical mast (not shown).

The multi-driven dipoles are interconnected with a two-wire line such as Wire rods 40, 41 which interconnect the various dipole units to the feed line T. These wire rods have a diameter of approximately 5 inch and may be spaced approximately 2% inches apart up to the point where they join the diverging rods 38, 39 to insure the proper impedance matching between units. These wire rods are offset in the configuration shown in FIG. 1, so as to increase the overall length of the rods beyond the physical spacing between the elements 1 and 3. The effective additional length of the line constituted of these rods enhances the transmission of signal by delaying the signal a predetermined amount.

In order to more fully understand the theory of operation of the antenna shown in FIGS. 1 and 2, reference may be had to FIG. 3. It should be understood that'the analysis, merely for explanation, will be predicated upon a frequency separation and wavelength separation between the high and low bands involving a factor of three. Referring to FIG. 3, numeral represents a basic folded dipole which is Veed forward to have an included angle which may be approximately degrees. When this dipole is one half-Wavelength on low band it is three half wavelengths on the high band. The instantaneous current distribution on low band is represented by the dot-dash curve 91, while the instantaneous current distribution on the high band is represented by the dashed curves 92. When operating at the high band, antiphase operation is overcome by the fact that the center half-wave section is located in a degree space relationship to the outer extreme half-wave section. The effectiveness in the high band is obtained by having three end-fed half-wave elements whose signals add in phase by a series connection. To further enhance operation on the high band, the special impedance matching stubs 90a, corresponding to the rods 17, 18, 22, 23 of FIG. 1, are added to the respective folded dipoles. The addition of these stubs shifts the basic impedance of the dipole when operating on the high band into a more favorable position when the dipole is used in a multi-driven array. FIG. 3A shows the relative voltage pattern of the unit dipole of FIG. 3 when it isoperating in a typical low band channel, for example television channel 4; the pattern is the well known figure eight with beamwidth of approximately 79 degrees. FIG. 3B shows the corresponding relative voltage pattern of a typical high band channel, for example television channel 10; the pattern retains the figure eight characteristics with the exception that some minor lobes are present. Here the addition of the three effectively co-linear dipoles result in a polar diagram that has half-power points that are approximately 32 degrees.

With respect to the evolution of the units 3, 4 of FIG. 1, reference may be had to FIG. 4, wherein numeral 93 represents a basic half-wave dipole whose terminal spacing s is rather large on the lower band. Impedance transformation from a large value which is associated with a dipole of large terminal spacing is accomplished by tapering the rods 94, 95 to a value of approximately 300 ohms, the dot-dashed curve 96 being the instantaneous current flow associated with low band operation. The tapered line 9495 at high band operation functions as an antenna represented schematically by the line 98, and the current distribution in the tapered line antenna is represented by the curve 99 which is in anti-phase with the current distribution in the outer ends 93. Anti-phase operation is overcome by virtue of this tapering of the rods 94, 95. When operating on high band, the end sections of the unit are effectively co-linear end-fed halfwave dipoles, the center supporting section (26 or 29) being a parasitically excited director for the center portion of the dipole, anti-phase operation being overcome by virtue of 180 degree space separation, the instantaneous current fiow being represented by the dotted curves 97. A further improvement at both operating bands may be obtained by replacing the end section of element 93 with a paddle or a folded section, as schematically shown in FIG. 4C, the results being additional bandwidth at both frequency bands.

FIG. 4A shows the horizontal polar diagram of the dipole unit of FIG. 4 when it is operating at the lower frequency band, the pattern being of the familiar figure eight pattern. The angular width of the polar diagram at the half-power points is approximately 79 degrees. FIG. 4B shows the corresponding horizontal polar diagram of the same dipole when it is operating at the higher frequency band. There are two major lobes and two minor lobes. The dipole has a certain amount of directivity due to the presence of the co-linear parasitically excited director associated with it. The combined effective half-wave dipoles produce a major lobe that has a halfpower angular beamwidth of approximately 34 degrees. This arrangement produces a gain of approximately 3.0 db over a tuned half-wave dipole on the high band.

It has been found that by constructing an antenna as described above it is possible to receive signals in widely separated frequency bands, for example the presently assigned television channels 2 through 6 and 7 through 13, with a uniform gain. A high order of directivity has been achieved as illustrated in FIGS. 5A and 5B which show relative power patterns of the antenna system of the invention on channels 4 and respectively.

Various changes and modifications may be made in the disclosed embodiment without departing from the spirit and scope of the invention. Furthermore, while the invention finds its greatest efiiciency with the particular combination of elements shown in FIG. 1 of the drawing, it will be understood that it is not limited to this particular combination, and is intended to cover subcombinations of the various elements, such as a single folded dipole unit (such as units 1 or 2); or a single linear dipole-parasitic reflector unit (such as the units 3 or 4); or a combination of such a folded dipole unit with such a linear dipole-parasitic unit.

Various changes and modifications may be made in the disclosed embodiment without departing from the scope of the invention. Furthermore, while the various antenna elements are shown schematically connected at right angles to the booms, which is their position when in actual use, it will be understood that one or more of the various antenna elements may be pivotally attached to its respective boom so as to enable the entire assembly to be collapsed to a substantially compact linear form. For a description of a typical such pivoted locking arrangement, reference may be had to U.S. Patent No. 2,843,848, issued July 15, 1958.

What is claimed is:

1. An antenna, comprising a first array consisting of first, second and third elements, a second array consisting of first, second and third elements, the first and third elements of each array constituting a half wave dipole with the inner ends gapped arranged to be connected to a feed line and with the second element located colinea-rly in said gap and constituting a parasitic director, means to support each array with the three elements thereof as a rigid unit and with the second array spaced forwardly of the first array, respective tapered feed lines for connection to a common transmission line, each feed line having the wider spaced ends connected to the respective gapped ends of the first and third elements of each array.

2. An antenna, according to claim 1, in which the second element of each of said arrays is insulatingly spaced from the gapped ends of the respective first and third elements of that array.

3. An antenna, according to claim 1, in which the three elements of each array are rigidly supported in substantially linear formation.

4. An antenna, comprising a V-shaped folded dipole having closely gapped inner ends arranged to be connected to a feed line and with the apex of the V facing rearwardly, a substantially linear array mounted in spaced relation forwardly of the folded dipole, said linear array consisting of three spaced elements the outer two of which form a half wave dipole with their inner ends widely gapped and the intermediate one of which is located colinearly between said gapped ends and forms a parasitic director for the median portion of the folded dipole, and a feed line connected to the gapped ends of said dipole and the said gapped ends of said linear array.

5. An antenna, according to claim 4, in which said feed line includes .a tapered feed line section which has its wider end connected to the said widely gapped inner ends of the said outer elements of said linear array.

6. An antenna, according to claim 4, in which the V-shaped folded dipole is provided with impedance matching stubs which are effective substantially only when the antenna is operating at the higher frequency band.

7. .An antenna, comprising a folded dipole which is dimensioned to form a half wave dipole at one frequency band, and which is arranged to act as a multi half wave dipole at a higher frequency band, said folded dipole having closely gapped inner ends arranged to be connected to a feed line, :a co-linear rigid array comprising first, second and third elements mounted forwardly of said folded dipole, the first and third elements of said array being in forward alignment with the end portions of the folded dipole and constituting another half wave dipole at the said higher frequency band and with a widely spaced feed gap between the inner ends of the first and third elements, the second element of said array being in forward alignment with the median section of said folded dipole and constituting a parasitic director for said median section and extending colinearly in said wide gap, and means to connect the gapped feed ends of the folded dipole and the gapped ends of the said first and third elements to a common transmission line.

8. An antenna, according to claim 7, in which the means for connecting the gapped ends of the first and third elements of said array to said transmission line comprises a tapered feed section having its narrowly spaced ends connected to said transmission line and its Widely spaced widely gapped ends connected to the inner ends of said first and third elements.

9. An antenna system for two frequency bands of respectively low and high frequency, comprising a main dipole antenna section, a main reflector section mounted rearwardly of the said main dipole section, .a main director section mounted forwardly of said main dipole section, said main dipole section comprising in spaced sequence forwardly of said main reflector section a first folded veshaped dipole, a second folded V-shaped dipole, a first co-li-near dipole-parasitic director array, :1 second co-linear dipole-parasitic director array, both said parasitic director arrays being mounted forwardly of said folded dipoles, the first c-o-linear array comprising first and third co-linear elements respectively in forward alignment with the end portions of said folded dipoles and constituting another half-wave dipole at the lower frequency band, the second element of said first array being in alignment with the median sections of said folded dipoles and constituting a parasitic director for said median sections, the second co-linear array also comprising first and third co-linear elements in forward alignment with the end portions of said folded dipoles and constituting another half-Wave dipole at the higher frequency band, the second element of said second array 7 being in alignment with the median sections of said folded tively the inner ends of the first and third sections of 5 I each of said arrays to a common transmission line.

References Cited in the file of this patent UNITED STATES PATENTS 2,648,768 Woodward Aug. 11, 1953 10 8 Guernsey et a1 Nov. 27, 1956 Schwartz et a1 Dec. 17, 1957 Guernsey Dec. 9, 1958 Guernsey Dec. 23, 1958 Anderson Apr. 18, 1961 Winegard Oct. 31, 1961 FOREIGN PATENTS Australia June 17, 1937 

9. AN ANTENNA SYSTEM FOR TWO FREQUENCY BANDS OF RESPECTIVELY LOW AND HIGH FREQUENCY, COMPRISING A MAIN DIPOLE ANTENNA SECTION, A MAIN REFLECTOR SECTION MOUNTED REARWARDLY OF THE SAID MAIN DIPOLE SECTION, A MAIN DIRECTOR SECTION MOUNTED FORWARDLY OF SAID MAIN DIPOLE SECTION, SAID MAIN DIPOLE SECTION COMPRISING IN SPACED SEQUENCE FORWARDLY OF SAID MAIN REFLECTOR SECTION A FIRST FOLDED V-SHAPED DIPOLE, A SECOND FOLDED V-SHAPED DIPOLE, A FIRST CO-LINEAR DIPOLE-PARASITIC DIRECTOR ARRAY, A SECOND CO-LINEAR DIPOLE-PARASITIC DIRECTOR ARRAY, BOTH SAID PARASITIC DIRECTOR ARRAYS BEING MOUNTED FORWARDLY OF SAID FOLDED DIPOLES, THE FIRST CO-LINEAR ARRAY COMPRISING FIRST AND THIRD CO-LINEAR ELEMENTS RESPECTIVELY IN FORWARD ALIGNMENT WITH THE END PORTIONS OF SAID FOLDED DIPOLES AND CONSTITUTING ANOTHER HALF-WAVE DIPOLE AT THE LOWER FREQUENCY BAND, THE SECOND ELEMENT OF SAID FIRST ARRAY BEING IN ALIGNMENT WITH THE MEDIAN SECTIONS OF SAID FOLDED DIPOLES AND CONSTITUTING A PARASITIC DIRECTOR FOR SAID MEDIAN SECTIONS, THE SECOND CO-LINEAR ARRAY ALSO COMPRISING FIRST AND THIRD CO-LINEAR ELEMENTS IN FORWARD ALIGNMENT WITH THE END PORTIONS OF SAID FOLDED DIPOLES AND CONSTITUTING ANOTHER HALF-WAVE DIPOLE AT THE HIGHER FREQUENCY BAND, THE SECOND ELEMENT OF SAID SECOND ARRAY BEING IN ALIGNMENT WITH THE MEDIAN SECTIONS OF SAID FOLDED DIPOLES AND CONSTITUTING A PARASITIC DIRECTOR FOR SAID MEDIAN SECTIONS, AND MEANS COMPRISING A PAIR OF TAPERED IMPEDANCE MATCHING FEED LINE SECTIONS CONNECTING RESPECTIVELY THE INNER ENDS OF THE FIRST AND THIRD SECTIONS OF EACH OF SAID ARRAYS TO A COMMON TRANSMISSION LINE. 